Concrete expansion joint



J. N. HELTZEL CONCRETE EXPANSION JOINT Jan. 4, 1955 3 Sheets-Sheet lFiled March 4. 1947 Q. 6 h/N WV n. www f 4, J ./V E... .....A w.\......L. u. n

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CONCRETE EXPANSION JOINT Filed March 4, 1947 3 Sheets-Sheet 2 Jan. 4,1955 l 1 N HELTZEL 2,698,560

Y CONCRETE EXPANSION JOINT Filed March 4, 1947 3 Sheets-Sheet 3 2@myn/fof?.

M J lv. Menzel.

United States Patent O CONCRETE EXPANSION JOINT John Nicholas Heltzel,Warren, Ohio; The Union Savings & Trust Company, Warren, Ohio, and CarlJ. Heltzel, executors of John N. Heltzel, deceased Application March 4,1947, Serial No. 732,170

Claims. (Cl. 94-18) This present invention relates to improvements inthe so-called beamed expansion joint. According to this jointconstruction a sill or beam of suitable material, such as concrete, isembedded in the subgrade of a road or airport runway at a pointpredetermined by its location beneath a proposed expansion orcontraction joint to be produced between a pair of concrete slabs. 'Ihesame are to be poured later or are to be placed over the beam.

The principal object of the invention is to provide a construction ofthe type characterized and including tension means connecting the beamto the slabs and permitting the latter to expand or contract in anydirection but preventing the slab ends from moving up and down. Thisconstruction also includes moisture absorbent means for relieving thetension of the plastic mass represented by each slab.

Another object of the invention is to provide a construction ascontemplated by the principal object of the invention and furthercharacterized by tension means stressed during the expansion of theslabs and by virtue of such stress contributing towards the relief ofthe tension developing in the slabs during the contraction.

A further object of the invention is to provide, in a construction ascharacterized, drainage means conducting the Water from the joint to thesubgrade.

Still another object of the invention is to provide, in a constructionas characterized, a beam including a surface supporting a pair of slabsand also including adjacent said slab-supporting surface drainage meansconducting the moisture to either side of the beam.

A still further object of the invention is to provide a contraction ordummy type joint.

With these and other objects in View which will become apparent as theinvention is fully comprehended, the same resides in the novelty ofconstruction, combination and arrangement of elements and method ofconstructing the combination of elements. Both the combination ofelements and the method of constructing the combination will hereinafterbe described in their specic details and are claimed in the subjoinedclaims.

The description should be read in connection with the accompanyingdrawings, forming part of the application and wherein:

Fig. l is a vertical section taken transversely of the joint structureforming the preferred embodiment of my invention;

Fig. lA is a fragmentary plan view of a portion of a highway or airportand illustrating the use of my slabsupporting beams below the joints ofthe highway;

Fig. 1B is a plan view of a slab-supporting beam incorporated in theinvention;

Fig. 2 is a view similar to Fig. 1 of a modied form of my joint;

Fig. 3 is a perspective view of another modified form of a beam or sillsubmerged in the subgrade.

Referring specifically to the drawings and having particular referenceto the form of invention disclosed in Figures l and 2, numeral 8designates the joint space between the opposed slabs 9 of a roadway,airport or the like, which slabs are supported upon the subgrade 10.

The joint space 8 is provided between slabs to allow for expansion andcontraction of same under diiferent atmospheric conditions, and as in myprior applications, identiiied earlier herein, I provide beam-like sills11 which are disposed in the subgrade across the joint space atintervals, these sills 11 serving as the load-supporting elements of myexpansion joint.

Nice

The sills or beams 11 are preferably made of reinforced concrete,bituminous or otherwise, and have their upper surfaces lying iiush withthe surface of the subgrade so that road grading machinery such asrollers or the like may operate over them and eiect proper seating ofsame in the subgrade. Of course the beams or sills 11 may be made ofother materials, and in the present instance they are preferablypre-formed in a factory or other place and hauled to the job.

The beams 11 are reinforced by a plurality of transversely extending,laterally spaced rods 12 extending substantially the full width of thebeams, which latter will preferably extend the full width of the twoslabs 9 which they sustain; and in the case of a three-slab roadway,which is to say, one of three slab width, the beams 11 may extend thefull width of all three slabs. Rods 12 are trussed or vertically oit-setas at 12a, for added strength and their ends are bent downwardly (12b)to form legs which serve as supports for the reinforcing assembly duringthe pouring of the concrete to form the beams 11.

Extending lengthwise of the beams or sills 11 are the reinforcing rods13. These, by choice, are arranged in pairs laterally spaced adjacentopposite sides of the beam and although it is not absolutely necessary,l iind it desirable to weld rods 13, as at 13a, to the transversereinforcing rods or members 12.

Figure l illustrates the reinforcing cross-rods 12 as having welded orotherwise secured to their under surfaces the medially apertured bearingplates 14. The welding referred to is indicated by reference character14a. In the illustrated embodiment of the invention nuts 1S are weldedor otherwise secured to the lower portions of the respective bearingplates 14, concentric with the apertures thereof, the welding beingindicated by reference character 15a. However, it is to be understoodthat the bearing plates 14 and the nuts 15 may be made integral.

In carrying out the sill or beam reinforcement, I provide verticaltubular members 16 arranged in pairs at opposite ends of the beam 11 andconcentric with openings in the bearing plates 14. It is also desirablethat the flared lower ends 16a of the tubular members 16 be welded tothe upper face of the bearing plates 14. The flared upper ends 16a ofthe tubular members 16 terminate flush or substantially flush with thetop surface of the beams, as indicated in Fig. l. There should beprovided a pair, or two tubular members 16 intermediate the ends of thebeams or sills 11. The number of tubular members 16 used will, ofcourse, depend upon the length of the sill or beam 11. The flaring ofthe upper and lower ends of the tubes, as indicated at 16a, serves togive same added strength and rigidity.

After the tubes 16 have been installed, the slab or sill 11 is pouredand iinished, it being observed that the upper ends of the tube 16 willnecessarily be temporarily plugged during the pouring of the sill. Whenthe sill or beam 11 has properly set, it is installed in the subgrade asshown in Figure l, the various other elements shown associated with thesill being applied thereto later after the subgrade is iinished and isready for the pouring of the slabs 9.

Figure l also illustrates vertically extending tension rods 17.

The upper ends of the vertically extending tension rods 17 are bentlaterally inward as at 17h, the said ends of companion rods 17 beingdisposed in opposition to one another so as to engage and retain theU-shaped cap strip 20 which is seated over the usual joint strip 21 ofcompressible material. Thus, the tension rod ends 17b serve to align thejoint strip 21 to retain it in vertical position during the pouring ofthe slabs 9.

It should here be observed that during the pouring and nishing of sillor beam 11, the vertical tension members 17 may be temporarily screwedinto position so as to facilitate stabilization of the tubular members16. This will assure accuracy of the centering of the tension members17. Assuming that the tension members 17 have been used as abovementioned when sill 11 is poured, they are temporarily removed so as notto interfere with grading machinery, rollers and the like, used toprepare the subgrade l0 for the pouring of the slabs 9.

Figure l also illustrates that the lower end of the joint strip 21 isreceived in a U-shaped channel strip 21a. Both of the channel strips 20,21a extend the full length of the joint strip 21. The channel strips-20,21a, as previously intimated, serve to properly align the top and bottomedges of the joint strip 21.

After the sills or beams 11 have been properly positioned in thesubgrade 10, and the latter has been rolled and otherwise prepared forthe pouring of the slabs 9, the upper surface of each of the sills orbeams 11 is covered with a layer of tar paper or the like 19, the ends19a of which are inclined inwardly into the subgrade and covered so asto retain the tar paper in position.

The function of the tar paper covering 19 for the beams or sills 11 isto insure complete separation of the slabs 9 from the subgrade and beamsor sills 11; and also to eliminate any possible resistance to theshifting of the slabs 9 on their supporting sills 11 during theexpansion and contraction of the slabs under action of differentatmospheric conditions. The tar paper sill covering 19 also assists inguarding against damage to the slabs 9 during the shrinking period ofthe plastic mass, there being also provided'means for relieving tensionof the mass during the drying process, which means will be dealt withhereinafter.

Still referring to Figure l, it will be noted that I dispose upon thetar paper 19, above the sills 11, tubular members 18 whose ared bottomportions 18a are concentric with the tubular members 16 and rest uponthe tar paper in alignment with the flared upper ends 16a of suchtubular members 16. The upper ends of the upper tubular members 18 havefrictionally or otherwise seated therein the inverted frusto-conicaldisks 1817 which are medially apertured for the tension rods 17 toextend therethrough. The tension rods 17 are, of course, screwed backinto the nuts after the subgrade with the sill 11 embedded therein hasbeen rolled and finished preparatory to pouring of the slabs 9. Theupper ends of the upper tubular members 18 terminate substantially shortof the inwardly bent portions 17b of the tension rods 17, asillustrated.

Before the slabs 9 are poured, reinforcing rods 22 are suitablypositioned and supported temporarily by any convenient means from thesubgrade, the position of said rods being in the bend between theinturned end 17b and the vertical portions of the tension rods 17. This,when the slabs 9 have been poured, the tension rods 17 in effect connectthe upper area of the slab with the subjacent joint spanning supportingbeam or sill 11.

Previous reference has already been made to means for relieving thetension of the plastic mass comprising each slab during the setting ordrying out process, and, as shown in Figure l, this takes the form of awooden bar 23 kwhich is co-extensive in length with the joint 8 betweenslabs 9. The wooden bar 23 as shown is square or rectangular in crosssection and rests upon the tar paper 19 centrally of the joint space 8.The bar 23 has been stated as being of wood but the primary or essentialcharacteristic of the bar 23 is that it must be highly absorbent so asto expand under the action of moisture and contract as it dries out.

The wooden bar 23 has disposed on either side the angle bars 24, thevertical flanges of the angle bars engaging said wooden bar 23, whilethe base flanges 24 thereof rest upon the tar paper covering 19 of thesill 11. The angle bars 24 may, and preferably do, extend the full widthof the associated slab and are pressure absorbing elements, to reinforcethe bottom portion of the slab 9 adjacent the tubular members 18.

Brace members 25, in the form of rods having laterally bent lower endportions 25h, engaging the angle bars 24 at the intersection of theirflanges', extend diagonally upward into the associated slab 9, and havetheir outer ends bent laterally, as at 25a, to effect an anchoring bondin the slab. The angle bars 24 and brace members 25 are, of course,located in the positions illustrated in Figure l, and are suitablyretained in place during the pouring of the slabs 9.

In order to hold the moisture-absorbent wooden or other bar Z3 in place,during the pouring of the concrete to produce the slabs 9, I providewires 26, whose inner terminals are nailed as at 27, to the absorbentbar 23, and have their outer ends provided with loops 26a extendingaround the upper tubular members 18, all as shown in Figure 1. It isdesirable that a compressible strip 28 be disposed on top of the woodenor other expansible bar 23, as shown in Figure 1. 28 may be of materialsuch as asphalt or it may be of fibrous moisture absorbing material suchas the composition commercially known as Celotex. The function ofcompressible strip 28 is to act as a cushion to at least partiallyabsorb upward expansion of the wooden bar 23 which would tend to elevatethe slabs 9.

It will be understood that during the pouring of the slabs 9, the uppertubular members 18 are sustained by the tension rods 17 extendingthrough the apertured medial portions of the inverted frusto-conicaltop-closures 18b of said tubular members. Thus, there will be no lateralshifting of the tension rods 17 in said tubular menbers during thepouring of the concrete to produce sla s 9.

Figure l also illustrates that the upper and lower tubular members 18,16, are filled with sealing filler 29. This ller material 29 ispreferably resilient, rubber being a Very satisfactory material to usefor this purpose. The lling material 29 serves to prevent infiltrationof foreign matter into the tubular members while permitting universallateral tlexation of the tension rods 17 within the contines of tubularmembers 16, 18.

After the road or airport has been placed in service, the tensionmembers 17 will connect the slabs 9 to the joint spanning beams or sills11 thereby preventing the slab ends from moving up and down butpermitting movement of the slabs 9 in all directions due to expansionand contraction.

When the slabs 9 are being poured, it will be obvious that the Wooden orother absorbent material bar 23 will absorb moisture and expand, forcingthe lower ends of said slabs 9 outwardly as they shrink in the dryingout process. This avoids the formation of fissures or the creation ofany weakened areas in the slabs as the result of tension as the slabsshrink in the drying out process. It is to be understood that the jointstrip 21, particularly after the road has been in service for some time,provides a very imperfect seal of the joint against moisture so thatwhen there is rainfall a substantial amount of water will reach thewooden bar or the equivalent 23. Then, of course, after the road orairport is in service and the slabs expand in dry hot weather, thewooden or other moisture absorbing bar 23 will contract to cornpensatefor such slab expansion. By the same token, in wet weather the bar 23expands assisting the normal tendency of the slabs' to shrink andproduce a widening of the joint space 8. The beam 11 has a plurality ofcentral drip passages 11b disposed under the bar 23, detailed referenceto which will be made in the description of Fig. 2.

In Figure 2, illustrating a modified form of my invention, numeral 8denotes the space between adjacent ends of slabs 9a supported by asubgrade 10 in which the sill or beam 11a is submerged. The sill or beam11a extends longitudinally and on either side of the space 8 andtransversely of the road or airport runway.

In the beam 11a is formed a desired plurality of drip or drainagepassages such as 11b for water which might enter at the top of theexpansion joint or at the top surface of the slab. During the wintermonths and when the temperature is low the water inltrates through thejoint formed by space 8 and is trapped in that position. This factjustifies the location of the drainage passages 11b directly under thejoint.

The water passing through the passage 11b filters into the subgrade orthe underpassage drain 11C, which extends throughout the entire lengthof the sill or beam 11a.

The underdrain 11e may also be useful for a purpose other than the onestated and affords a means whereby a beam 11a that has become depressedin the subgrade may be elevated by forcing ballast beneath the beam.This is carried out by pneumatic rams operated from the edges of theroadway and taking the place of the mud-jack, well known in the art.

Lengthwise of each beam 11a extend, in spaced relation, a plurality ofhorizontal reinforcing rods 13.

The medially apertured bearing plates 14 are arranged in pairs and theunderside of each plate 14 is welded to the upper end of a nut 15 and isalso welded or otherwise secured to the bottom end of the aring lowerportion 16a of a tubular member 16. An apertured rubber or othercompressible material plug or disk 16x closes the lower ared tubeportion 16a and the adjacent tube part.

This' compressible strip L The upper end 16a of each tube 16 is likewiseflared as at 16a and is also closed by a similar apertured plug 16x. Thetubes or sleeves 16', 18 are encased in the beam 11a.

A pair of vertical tubes 1S in spaced relation are each arranged in aslab and have a lower flaring end 18a in substantial alignment with oneof the lower tubes 16'. The upper tubes 18 have their upper ends pluggedby apertured plugs 18b.

ln this connection the question might be raised as to Whether it ispossible to entirely eliminate the so-called pumping of the subgrade.However, constructing the sills or beams 11a as submerged in thesubgrade and the provision of passage 11e will do away with most of thepumping tendency owing to the fact that a cushion member 19, having itsend portions 19a embedded in the subgrade, is laid across the top of thebeam 11a.

This cushion member 19 may consist of asphalt composition and will,therefore, reduce the friction between the bottom of the slabs 9a andtop of the beam 11a. Figure 2 shows the cushion member crimped at anintermediate zone 19b, owing to the approaching or expanding movement ofthe slabs 9a. The cushion member 19 absorbs the shocks of traic passingover the joint. Thus, pumping of the subgrade is minimized and slabcurling prevented. Experts in the art realize that pumping is due toVibration of the slab 9a at the joints. By my construction. suchvibration is largely eliminated.

The joint space 8 is occupied by an expansion joint strip 21' which. asillustrated in Figure 2, has been compressed by the approachingexpanding movement of the slabs 9a. (ln Figure l the slabs 9, on thecontrary, are shown contracted and the expansion joint strip 21uncompressed.)

A pair of horizontal reinforcing rods 22 are suitably positioned priorto the pouring of slabs 9a and supported temporarily by any availablemeans from the subgrade and each located in the bend between theinturned portion 30b and the vertical part of a tension rod 36. Theinturned portion 30b of each tension rod 30 has a free beveled endengaging the vertical side of the joint strip 21'.

Tension rods 30 are of standard reinforcing steel and may also begalvanized or made otherwise rust-proof. Fig. 2 indicates deformationson the rods 30, each of which extends near its lower end through theaperture of a bearing plate 14 and is threaded at such end forconnection to a nut 15. The reinforcing steel for the rods 30 may behigh carbon rerolled material of a very high tensile strength.

The use of deformed material for rods 30 will provide anchorage in thetop portion of the slab. The unusual rigidity of this high carbonmaterial insures corresponding resistance to bending.

31 denotes one of a desired plurality of reinforcing cross rods embeddedin spaced relation and horizontal position in the beam 11a and extendingsubstantially the full width thereof.

Each cross rod 31 is secured by welding or otherwise at points spaced onits underside to the tops of the bearing plates 14 and supports the sameand the structure resting upon said plates 14. The end portions of rod31 comprise vertical legs 31a. preferably formed by bending, and theyterminate in horizontal feet 3111 bent laterally of the legs and in thevertical plane of the latter and of the horizontal part of rod 31.Preferably, each rod 31 is welded or otherwise secured on its uppersurface to the lower surfaces of rods 13.

The lower edge portion of the joint strip 21 is seated in a recess 32aextending longitudinally of, and in the ton portion of, a wooden bar 32which is thus held in alignment by the joint strip. Wooden bar 32 isshown in a compressed condition brought about by a previous movement ofthe slabs 9a toward one another. (ln Figure l, for contrast, thecorresponding wooden bar 23 is shown as uncompressed.)

The lower edge of wooden bar 32 is formed with a lineal recess or groove3217 which receives the crimped zone 19b of the cushion member 19, when,as shown, the slabs are expanded.

The major lower portions of the vertical sides of the wooden bar 32 areeach engaged by the vertical flange 33a of a cover plate 33 whose planehorizontal portion closes the top opening of a sleeve 16. Each coverplate 33 has its plane horizontal portion provided with an opening 33efor passage of a tension rod 30.

Each cover plate 33 terminates in outer upwardly rising terminalportions 33b with an anchoring hole 33c for the concrete.

As will be apparent, the cover plates 33 act through their verticalanges 33a to properly position the wooden bar 32 under the joint spacewhile slabs 9a are being poured.

During the expansion of the slabs 9a the latter exert an inwardlydiverted force against the vertical flanges 33a of cover plates 33 withthe result that the opening 33e thereof engages its rod 30 at a pointremote from the joint and ilexes said rod 30 inwardly as shown in dottedlines in Figure 2.

The tension members or rods 30 tend to resist the movement of the slabs9a toward one another. The bending stress to which the rods 30 have beensubjected urges the slabs 9a to move apart and away from the joint 8.This relieves the concrete slabs 9a from tension during contraction.

So that cover plates 33 may be made of lighter gauge material than wouldotherwise be possible, a deformation 33d is pressed in adjacent portionsof the horizontal part and vertical llange portion intermediate thesides of said plate. (See left hand plate 33 as viewed in Figure 2; andalso dotted lines in right hand plate 33 in Figure 2.)

One of the great difficulties in connection with structures of the typedescribed is the accumulation of moisture in the joint 8 and beneath theslabs 9a and about parts, such as 33, 18, etc., which are submerged inthe concrete. This moisture becomes especially detrimental to thestructure when the moisture is trapped and freezes.

The drainage of the moisture is accomplished by the provision of atubular member 35 which, at its ends, communicates with the tubes 16 andincludes sloping portions emptying the drainage into the passage 11b andfrom there to the drain 11C.

The casting of the beam and slab is done in a manner similar to the oneoutlined in the description of the preferred embodiment.

During the contraction of the slabs excessive stresses may develop whichare, however, relieved by the resistances of the joint strip 21', andthe wooden bar 32 and the bending stress prevailing in the verticalportions of rods 30.

Figure 3 shows a modified form of sill or beam 41 submerged in thesubgrade 42. Preferably, this beam extends completely across the roadwayand below the joint space 43 between adjacent ends of the slabs 44. Abeam extending completely across a multiple slab width roadway wouldundoubtedly, as a practical proposition, have to be poured on the job.However, a plurality of sills or beams laid end to end and possiblyprecast and hauled to the place, could replace the single beam.

instead of relying on the structural rigidity of the sill or beam tocarry a load, it may appear desirable to reinforce the beam by rigidsteel members 45 embedded therein and extending transversely thereof orlongitudinally of the roadway. The members 45 may have spaced holes 45athrough which the concrete exgelnds and which thus provide an anchoragein the beam Angle irons or channels could be the form taken by members45 which preferably are reinforced and supported at their ends by spacermembers 46. Said spacer members 46 are each welded to an upturned endportion 47a of a subjacent reinforcing member 47 disposed transverselyof the joint.

Anchorage terminal members 48 are each seated in sockets 49 and coveredby covers 50 and each of said terminal members 48 have in their lowerportion a notch 51 receiving a rib 52 forming on the interior of thecover 50 and holding the terminal member 48 against rotation. The covers50 are water-tight and are filled with a supply of lubricant. Theterminal members 48 are threaded at their upper ends projecting throughthe sockets for grgagement by threaded end parts of tension members Thelower part of each tension member 53 is surrounded by a tube 54 bearingwith its lower end against the upper side of the adjacent socket 49 andwith its upper flared end against the upper ange of the beamreinforcingmember 45, which ange is apertured for theA passage of the tensionmembers 53.

The members of the Figure 3 disclosure so far described form part of thebeam 41 structure and may be encased with either concrete or bituminousmaterial. If the rigidity of member 45 is ample, the same may be encasedin bituminous material for protection against 1'11St.

The use of bituminous material as a rust-induced deteriorationpreventer, as stated for member 45, makes it possible in many instancesto dispense with the spacing and reinforcing means 46 and 47. Such wouldbe the case where means 46 and 47 were used in conjunction with 45 tosupply strength to supplement that of 45 when partially rusted away.However, similar means could be used for supporting members 45 inposition during the application of the bituminous material. The use ofconcrete in the formation of beam 45 will make it possible to use alighter member 45 than would be the case otherwise.

It may prove practical to position the beam 45 elements so far describedon the subgrade, and to then pour the concrete and surface it so thatthe resulting beam has a top bearing portion flush with the subgrade.Care should be taken to prevent the infiltration of any concrete into atubular member 54, since such concrete might interfere with theinsertion and proper subsequent swinging operation of the tension member53 upon expansion and contraction of slabs 44.

After the beam 41 has been placed in proper position, an asphalt orother cover strip 56 is placed over the structure to promote relativefreedom of movement of slabs 44 on beam 41.

Then the expansion or joint strip 57 and the supporting members 58 aremounted on the cover strip 56 so that the vertical portions of theformer hold the joint strip 57 in a vertical position during the pouringof the slabs. The bottom portions 58h of members 58 function as slidesor skids during the expansion or contraction of the slabs 44.

58e denotes lineally extending reinforcing ribs pressed into members 58intermediate its ends to rigidify the same and enable me to use lightergauge material than would otherwise be possible. The upper and lowerangularly directed ends of members 58 are provided with holes 58d foranchoring purposes.

The slide or base portion 58b of each member 58 is provided with anopening 58e registering with an opening in the horizontal ange or webmember 45. Each tension member 53 is inserted through these openings inthe members 45 and 58 and is surrounded by a tubular 1 member 62preventing the infiltration of foreign matter.

The upper end of each tension member 53 is formed by a knob-liketerminal member 63 capable of universal movement in socket 64 resting ontop of the tube 62 and covered by cap or cover 65. The terminal member63 has on its upper side a notch 63a for the insertion of a wrench-likeimplement whereby the tension rod 53 may be turned and threaded into orout of the part 48. The insertion of the wrench must, of course, bepreceded by the removal of the cap 65 which, in its operative position,prevents the entry of foreign matter.

In order to properly space rigid members 45, spacers 67 extendinglongitudinally of the beams 41 are provided and secured to the former.

Drainage and friction are important factors in expansion joints. Inorder to reduce the friction on the top surface of the sill on which theslabs bear, and at the same time to provide for drainage, the top of thesill is provided with corrugations 68 spaced from one another by drainchannels 69 sloping downward from the bottom of the expansion joint.

The asphalt cover 56 is positioned between the top surfaces of thecorrugations 68 and the bottom surfaces of the slabs 44 and facilitatesthe shifting of the latter on the former. In addition, a lubricant maybe applied to the asphalt cover 56.

Moisture, having infiltrated through the expansion joint or otherwise,will be diverted to the drain channels 69. This drainage also relievesthe tension members 53 of excessive strains otherwise imposed on them bythe freezing of the moisture.

The top surfaces of the corrugations 68 are level and lie ush, or inplane with, the subgrade of the roadway. The tension members 53 areanchored in the corrulgatiogns 68 and do not project through the drainchanne s I desire it to be understood that the corrugated (68) basey orbeam 41 proposition with the drainage channels 59 may be used inconnection with contraction joints, also called dummy-type joints.

While I have hereinbefore described the specic details of variousembodiments of my invention illustrated in the accompanying drawings, Idesire it to be understood that changes or modifications of thesedetails, falling within the scope of the appended claims, may beresorted to without departing from the spirit or scope of the invention.

What I claim is as follows:

1. In a roadway or runway construction, a subgrade, a beam submerged insaid subgrade, an upwardly extending bar secured in said beam atopposite sides of its lineal center, each bar having its major portiondisposed above the beam and universally movable in lateral directions,tube means secured in said beam inwardly from the top surface of thelatter and ush therewith,

said tube means spacedly surrounding the beam-carriedl end of said bar,a pair of slabs supported by said beam on opposite sides of the linealcenter thereof and spaced from one another to provide a joint space,each of said slabs anchoring the other end of one of said beam-carriedbars, inwardly extending tubes carried by said slabs and spacedlysurrounding said bars, said respective slab and beam-carried tubes beingaligned with one another, an absorbent moisture expandable barinterposed in said joint space, a slab-carried reinforcement member foreach slab and bearing against said absorbent bar, and each slab-carriedreinforcement member having a portion embracing the related beam andslab connecting bar whereby expansion of said absorbent bar appliesforce to said slab and beam connecting bars.

2. In a roadway or runway construction, a subgrade, a beam submerged insaid subgrade, tension means anchored in said beam, tubes in said beamopening from the top surface thereof and enclosing said tension means inspaced relation, a pair of slabs supported by said beam and includingend portions adjacent to and spaced from one another, said tension meansbeing also anchored in said slabs, other tubes in the slabs opening fromthe bottom surfaces thereof and enclosing said tension means in spacedrelation, said tension means permitting relative horizontal movement ofsaid slabs on said beam, means connecting said other tubes andpreventing outward movement thereof, angles slidable on said beam andengaged by said slab ends, brace members each engaging an angle andanchored in said slabs, and an absorbent moistureexpandable bar betweensaid slab ends and angles.

3. In a roadway or runway construction a subgrade, a beam submerged insaid subgrade, tension means anchored in said beam, tubes opening fromthe top surface of said beam and surrounding said tension means inspaced relation, a pair of slabs supported by said beam and includingend portion adjacent to and spaced from one another, said tension meansbeing also anchored in said slabs, other tubes in the slabs opening fromthe bottom surfaces thereof and surrounding said tension means in spacedrelation, an absorbent moistureexpandable bar between said slab endportions and supported by said beam, and drainage means in said beambelow said absorbent bar in communication therewith and connected to andcommunicating into said first tubes.

4. In a roadway or runway construction a subgrade, a beam submerged insaid subgrade, tension means anchored in said beam, tubes opening fromthe top surface of said beam and surrounding said tension means inspaced relation, a pair of slabs supported by said beam and includingend portions adjacent to and spaced from one another, said tension meansbeing also anchored in said slabs, other tubes surrounding said tensionmeans in spaced relation in said slabs opening from the bottom surfacesthereof, said tension means permitting relative horizontal movement ofsaid slabs on said beam, cushion means between said beam and slabs andfirst and second tubes, an absorbent moisture-expendable bar betweensaid slab end portions and supported by said beam, said bar having arecess for a zone of the cushion means crimped during expansion of theslabs, and drainage means in said beam below said absorbent bar andcommunicating therewith.

5. In a roadway or runway construction a subgrade, a beam submerged insaid subgrade, tension means anchored in said beam, tubes opening fromthe top surface of said beam and surrounding said tension means inspaced relation, a pair of slabs supported by said beam and includingend portions adjacent to and spaced from one another, amoisture-expandable bar in the space between said slabs, said tensionmeans being also anchored in said slabs, other tubes surrounding saidtension means in spaced relation in said slabs and opening from thebottom surfaces thereof, said tension means permitting relativehorizontal movement of said slabs on said beam, slab-carriedreinforcement means engaging said tension means between said iirst andsecond tubes and stressing said tension means during expansion andcontraction of said slabs, and said bar engaging said slab-carriedreinforcement means for stressing said tension means.

6. In a road or airport runway construction or the like includingsubgrade-supported slab members spaced from one another to provide anexpansion joint therebetween, and a beam member embedded in the subgradebelow and paralleling the joint between the slab members; thecombination of an absorbent, moisture-expandable bar supported on saidbeam member at the site of said expansion joint and extending lengthwiseof the latter, said bar being of a width exceeding the maximum width ofsaid expansion joint and of a thickness materially less than thethickness of said slab members, said slab members having opposedbar-receiving bottom recesses at the site of said joint and providingshoulders overlying portions of the bar top, at opposite sides of thejoint, the bottom of said bar lying substantially ush with the bottomsurfaces of said slab members, said beam member having drainage meansextending therethrough from its top surface and located below saidjoint, the top of the beam member lying substantially flush with thebottoms of the slab members and bar, and upstanding relative horizontalmovement-permitting tie means connecting said beam and slab members atopposite sides of said expansion joint, there being a yieldpermittingrelief area surrounding each of said tie means and extending into atleast one of said slab and beam members, whereby the tie membersmaintain the beam member in contact with the under surface of saidexpandable bar and slab members at opposite sides of said expansionjoint so as to assure of drainage from the joint and expandable barreaching the drainage means of said beam member.

7. In a road or airport runway construction or the like includingsubgrade-supported slab members spaced from one another to provide anexpansion joint therebetween, and a beam member embedded in the subgradebelow and paralleling the joint between the slab members; thecombination of an absorbent moisture-expendable bar supported on saidbeam member at the site of said expansion joint and extending lengthwiseof the latter, said bar being of a width exceeding the maximum Width ofsaid expansion joint and of a thickness materially less than thethickness of said slab members, said slab members having opposedbar-receiving bottom recesses at the site of said joint and providingshoulders overlying portions of the bar top, at opposite sides of thejoint, the bottom of said bar lying substantially ush with the bottomsurfaces of said slab members, the top of the beam member lyingsubstantially ush with the bottoms of the slab members and bar, andupstanding relative horizontal movement-perrnitting tie means connectingsaid beam and slab members at opposite sides of said expansion joint,and there being a yield-permitting relief area surrounding each of saidtie means and extending into at least one of said slab and beam members,whereby the tie members maintain the beam member in contact with theunder surface of said expandable bar and slab members at opposite sidesof said expansion joint.

8. In a road or airport runway construction or the like includingsubgrade-supported slab members spaced from one another to provide anexpansion joint therebetween, and a beam member embedded in the subgradebelow and paralleling the joint between the slab members; thecombination of an absorbent, moisture-expandable bar supported on saidbeam member at the site of said expansion joint and extending lengthwiseof the latter, said bar being of a width exceeding the maximum width ofsaid expansion joint and of a thickness materially less than thethickness of said slab members, said slab members having opposedbar-receiving bottom recesses at the site of said joint and providingshoulders overlying portions of the bar top at opposite sides of thejoint, a compressible pad means interposed between said bar andshoulders, the bottom of said bar lying substantially ush with thebottom surfaces of said slab members, the top of the beam member lyingsubstantially ush with the bottoms of the slab members and bar, andupstanding relative horizontal movement-permitting tie means connectingsaid beam and slab members at opposite sides of said expansion joint,and there being a yield-permitting relief area surrounding each of saidtie means and extending into at least one of said slab and beam members,whereby the tie members maintain the beam member in contact with theunder surface of said expandable bar and slab members at opposite sidesof said expansion joint.

9. In a road or airport runway construction or the like includingsubgrade-supported slab members spaced from one another to provide anexpansion joint therebetween, and a beam member embedded in the subgradebelow and paralleling the joint between the slab members; thecombination of an absorbent, moisture-expandable bar supported on saidbeam member at the site of said expansion joint and extending lenghwiseof the latter, said bar being of a width exceeding the maximum width ofsaid expansion joint and of a thickness materially less than thethickness of said slab members, said slab members having opposedbar-receiving bottom recesses at the site of said joint and providingshoulders overlying portions of the bar top at opposite sides of thejoint, a compressible pad means interposed between said bar andshoulders, the bottom of said bar lying substantially lush with thebottom surfaces of said slab members, said beam member having drainagemeans extending therethrough from its top surface and located below saidjoint, the top of the beam member lying substantially ush with thebottoms of the slab members and bar, and upstanding relative horizontalmovement-permitting tie means connecting said beam and slab members atopposite sides of said expansion joint, there being a yield permittingrelief area surrounding each of said tie means and extending into atleast one of said slab and beam members, whereby the tie membersmaintain the beam member in contact with the under surface of saidexpandable bar and slab members at opposite sides of said expansionjoint so as to assure of drainage from the joint and expandable barreaching the drainage means of said beam member.

10. ln a roadway or runway construction, a subgrade, a beam submerged insaid subgrade, tension means anchored in said beam, tubes opening fromthe top surface of said beam and surrounding said tension means inspaced relation, a pair of slabs supported by said beam and includingend portions adjacent to and spaced from one another, said tension meansbeing also anchored in said slabs, other tubes surrounding said tensionmeans in spaced relation in said slabs and opening from the bottomsurfaces thereof, said tension means permitting relative horizontalmovement of said slabs on said beam, cushion means between said beam andslabs and irst and second tubes, an absorbent moisture-expandable barbetween said slab end portions and supported by said beam, and said barhaving a recess for a zone of the cushion means crimped during expansionof the slabs.

References Cited in the le of this patent UNITED STATES PATENTS1,739,102 Strauss Dec. 10, 1929 2,050,290 Earley et al Aug. 11, 19362,072,381 Post Mar. 2, 1937 2,148,773 Ozias Feb. 28, 1939 2,201,824Brickman et al. May 21, 1940 2,244,315 Ridgeway June 3, 1941 2,254,885Carswell et al. Sept. 2, 1941 2,319,049 Fischer May 11, 1943 2,330,213Heltzel Sept. 28, 1943 2,342,181 Crom Feb. 22, 1944 2,479,434 Van LondonAug. 16, 1949 FOREIGN PATENTS 321,495 Great Britain of 1929 562,495Germany of 1932

